<template>
  <a-cascader
    v-model:value="state"
    :options="options"
    :load-data="loadData"
    change-on-select
    @change="handleChange"
    :displayRender="handleRenderDisplay"
  >
    <template #suffixIcon v-if="loading">
      <LoadingOutlined spin />
    </template>
    <template #notFoundContent v-if="loading">
      <span>
        <LoadingOutlined spin class="mr-1" />
        {{ t('component.form.apiSelectNotFound') }}
      </span>
    </template>
  </a-cascader>
</template>
<script lang="ts">
import { defineComponent, PropType, ref, unref, watch, watchEffect } from 'vue'
import { Cascader } from 'ant-design-vue'
import { isFunction, get, omit } from '@admin/utils'
import { useI18n } from '@admin/locale'
import { useRuleFormItem } from '@/hooks/component/useFormItem'
import { LoadingOutlined } from '@ant-design/icons-vue'

interface Option {
  value: string
  label: string
  loading?: boolean
  isLeaf?: boolean
  children?: Option[]
}
export default defineComponent({
  name: 'ApiCascader',
  components: {
    LoadingOutlined,
    [Cascader.name]: Cascader,
  },
  props: {
    value: {
      type: Array,
    },
    api: {
      type: Function as PropType<(arg?: Recordable) => Promise<Option[]>>,
      default: null,
    },
    numberToString: { type: Boolean },
    resultField: { type: String, default: '' },
    labelField: { type: String, default: 'label' },
    valueField: { type: String, default: 'value' },
    childrenField: { type: String, default: 'children' },
    asyncFetchParamKey: { type: String, default: 'parentCode' },
    immediate: { type: Boolean, default: true },
    // init fetch params
    initFetchParams: {
      type: Object as PropType<Recordable>,
      default: () => ({}),
    },
    // 是否有下级，默认是
    isLeaf: {
      type: Function as PropType<(arg: Recordable) => boolean>,
      default: null,
    },
    displayRenderArray: {
      type: Array,
    },
  },
  emits: ['change', 'defaultChange'],
  setup(props, { emit }) {
    const apiData = ref<any[]>([])
    const options = ref<Option[]>([])
    const loading = ref<boolean>(false)
    const emitData = ref<any[]>([])
    const isFirstLoad = ref(true)

    const { t } = useI18n()

    // Embedded in the form, just use the hook binding to perform form verification
    const [state] = useRuleFormItem(props, 'value', 'change', emitData)

    watch(
      apiData,
      (data) => {
        const opts = generatorOptions(data)
        options.value = opts
      },
      { deep: true },
    )

    function generatorOptions(options: any[]): Option[] {
      const { labelField, valueField, numberToString, childrenField, isLeaf } =
        props
      return options.reduce((prev, next: Recordable) => {
        if (next) {
          const value = next[valueField]
          const item = {
            ...omit(next, [labelField, valueField]),
            label: next[labelField],
            value: numberToString ? `${value}` : value,
            isLeaf:
              isLeaf && typeof isLeaf === 'function' ? isLeaf(next) : false,
          }
          const children = Reflect.get(next, childrenField)
          if (children) {
            Reflect.set(item, childrenField, generatorOptions(children))
          }
          prev.push(item)
        }
        return prev
      }, [] as Option[])
    }

    async function initialFetch() {
      const api = props.api
      if (!api || !isFunction(api)) return
      apiData.value = []
      loading.value = true
      try {
        const res = await api(props.initFetchParams)
        if (Array.isArray(res)) {
          apiData.value = res
          return
        }
        if (props.resultField) {
          apiData.value = get(res, props.resultField) || []
        }
      } catch (error) {
        console.warn(error)
      } finally {
        loading.value = false
      }
    }

    async function loadData(selectedOptions: Option[]) {
      const targetOption = selectedOptions[selectedOptions.length - 1]
      targetOption.loading = true

      const api = props.api
      if (!api || !isFunction(api)) return
      try {
        const res = await api({
          [props.asyncFetchParamKey]: Reflect.get(targetOption, 'value'),
        })
        if (Array.isArray(res)) {
          const children = generatorOptions(res)
          targetOption.children = children
          return
        }
        if (props.resultField) {
          const children = generatorOptions(get(res, props.resultField) || [])
          targetOption.children = children
        }
      } catch (e) {
        console.error(e)
      } finally {
        targetOption.loading = false
      }
    }

    watchEffect(() => {
      props.immediate && initialFetch()
    })

    watch(
      () => props.initFetchParams,
      () => {
        !unref(isFirstLoad) && initialFetch()
      },
      { deep: true },
    )

    function handleChange(keys, args) {
      emitData.value = keys
      emit('defaultChange', keys, args)
    }

    function handleRenderDisplay({ labels, selectedOptions }) {
      if (unref(emitData).length === selectedOptions.length) {
        return labels.join(' / ')
      }
      if (props.displayRenderArray) {
        return props.displayRenderArray.join(' / ')
      }
      return ''
    }

    return {
      t,
      state,
      options,
      loading,
      handleChange,
      loadData,
      handleRenderDisplay,
    }
  },
})
</script>
